My bet is intake boot but ccv is possible but less likely. The service advisors tend to never like to own up to warranty items on older cars.
If car is still at dealer call their bluff now that you know that their initial diagnosis is under warranty. It won't take long for the diagnosis to change. Have some fun with them...then go to a Indy....this issue is so common with the m54 motor at this age the dealer should be ashamed at the misdiagnosis.
Last edited by x3brian; 01-23-2013 at 12:48 PM.